Comparison of miCrostruCture, ageing effeCt and shape memory properties of additively manufaCtured niti alloy using lens and eBam methods samples prepared using various additive manufacturing methods were compared in terms of structure, texture, transformation temperature and superelastic properties.samples manufactured using laser engineered net shaping (leNs) method showed texture several degrees deviated from the <001> build direction, however with composition near to the initial powder composition, enabling superelastic effect.The electron beam additive manufacturing (eBaM) samples showed martensitic structure at room temperature due to a shift of transformation temperatures to the higher range.This shift occurs due to a lower Ni content resulting from different processing conditions.However, eBaM method produced sharper <001> texture in the build direction and made it possible to obtain a good superelastic effect above room temperature.intermetallic particles of size 0.5-2 mm were identified as Ti 2 Ni phase using eDs and electron diffraction analyses.This phase was often formed at the grain boundaries.Contrary to the leNs method, the eBaM prepared samples showed Ni-rich primary particles resulted from different processing conditions that reduce the Ni content in the solid solution thus increase the martensitic transformation temperature.ageing at 500°C allowed for shifting the martensitic transformation temperatures to the higher range in both, leNs and eBaM, samples.it resulted from the formation of Ni rich coherent precipitates.in samples prepared by both methods and aged at 500°C, the presence of martensite B19' twins was observed mainly on {011} B19' planes.

Nickel titanium

10.24425/amm.2023.145480

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The Tribaloy T-800 Coatings Deposited by Laser Engineered Net Shaping (LENSTM)

Materials (2019)

T. Durejko Magdalena Łazińska Julita Dworecka-Wójcik Stanisław Lipiński Robert A. Varin

A Tribaloy family of alloys (CoMoCrSi) are characterized by a substantial resistance to wear and corrosion within a wide range of temperatures. These properties are a direct result of their microstructure including the presence of Laves phase in varying proportions. Tribaloy T-800 exhibits the highest content of Laves phase of all other commercial Tribaloy alloys, which provides high hardness and wear resistance. On the other hand, a large content of the Laves phase brings about a high sensitivity to brittle fracture of this alloy. The main objective of this work was a development of the Tribaloy T-800 coatings on the Ni-based superalloy substrate (RENE 77), which employs a Laser Engineered Net Shaping (LENSTM) technique. Technological limitations in this process are susceptibility of T-800 to brittle fracture as well as significant thermal stresses due to rapid cooling, which is an inherent attribute of laser techniques. Therefore, in this work, a number of steps that optimized the LENSTM process and improved the metallurgical soundness of coatings are presented. Employing volume and local substrate pre-heating resulted in the formation of high quality coatings devoid of cracks and flaws.

Laves phase

Brittleness

Near net shape

10.3390/ma12091366

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Citations (24)

Thermo-oxidative aging of the polyoxymethylene (POM), acrylonitrile–butadiene–styrene (ABS) and polycarbonate (PC) polymers – a comparative study

Journal of Polymer Research (2022)

Marcin Konarzewski T. Durejko Magdalena Łazińska Magdalena Czerwińska Piotr Prasuła

Polyoxymethylene

Polycarbonate

Acrylonitrile butadiene styrene